🪵 Why a “2×4” Isn’t Always Exactly 2×4

If you’ve ever ordered timber in the UK, you’ve probably noticed that sizes can be described using both imperial and metric measurements. This can feel confusing at first — especially when the size you receive doesn’t match the numbers you had in mind.

This page explains why that happens, and how to order timber with confidence.

🇬🇧 Why the UK Uses Both Imperial and Metric

Since 1 January 2000, UK retail regulations require timber to be sold using metric measurements.

However, many tradespeople and DIY customers still use traditional imperial terms such as:

• 2×4

• 4×2

• 1×6

These terms are deeply ingrained in the industry and are still widely used as shorthand — even though the actual timber is supplied in metric sizes.

As a result, the UK timber trade now operates using a mix of both systems.

📏 Imperial to Metric: Not an Exact Match

Imperial and metric sizes do not convert perfectly.

For example:

• A true 2" × 4" equals 50.8mm × 101.6mm

In reality, timber merchants don’t supply timber to those exact measurements. Instead, sizes are rounded to standard metric dimensions, typically within a few millimetres.

So when someone asks for:

• 2×4 timber

What they usually receive is:

• 50mm × 100mm

This rounding is normal, industry-standard, and expected.

✅ Why Metric Sizes Matter

Because imperial sizes don’t convert exactly, metric measurements should always be treated as the accurate size.

When ordering timber:

• Metric sizes define the actual dimensions supplied

• Imperial sizes are best viewed as traditional references, not precise measurements

Specifying metric sizes removes ambiguity and ensures you get exactly what you need for your project.

🛠 How Timber Merchants Interpret Sizes

Across the UK timber trade, it’s generally assumed that:

If a customer asks for an imperial size, they are referring to the nearest metric equivalent.

So:

• 2×4 = 50mm × 100mm

• 4×2 = 100mm × 50mm

This isn’t guesswork — it’s long-established industry practice.

🌲 Our Approach at Nottage Timber Merchants

At Nottage Timber Merchants, we understand that customers think and work in different ways.

That’s why:

• We display both metric sizes and imperial equivalents on our products

• Metric sizes are always shown as the primary reference

• Imperial measurements are included as a helpful guide

This approach helps bridge the gap between traditional terminology and modern standards — without confusion.

🧠 In Summary

✔ Timber in the UK is sold in metric sizes
✔ Imperial sizes are still widely used as shorthand
✔ Conversions are approximate, not exact
✔ Always rely on metric dimensions for accuracy

If you’re ever unsure which size is right for your project, our team is always happy to help — just ask.